01 -
Slice the potatoes into thin, ⅛-inch rounds. Keep them in water so they don't turn brown while you prep other parts of the dish.
02 -
Heat the oven to 350°F. Coat a 9x13 dish with a nonstick spray.
03 -
Over medium-high heat in a large pot or pan, cook the ground beef, onions, and garlic. Stir and break it into crumbles as it cooks. Strain off extra grease.
04 -
In a mixing bowl, combine the mushroom soup, half-and-half, onion powder, salt, and pepper using a whisk.
05 -
Pour the water out from the potato bowl. Put a third of the sliced potatoes into the baking dish, followed by a third of the ground beef, ¾ cup of shredded cheese, then a third of the sauce.
06 -
Repeat the layering two more times and finish it off with 1½ cups of cheese on top.
07 -
Cover the dish with foil and bake for about 1 hour and 10 minutes. Remove foil and bake for another 20 minutes until the cheese is bubbly and golden.
08 -
Let the casserole cool off for 15 minutes before digging in—it'll be hot!